NEW APPROACH TO TORSIONAL VIBRATION MONITORING
Abstract
This paper presents a summary of the authors' experience
gained from implementation of model-based monitoring
systems for LNG string vibration. The development of a novel
train torsional vibration monitoring approach utilizing system
modal analysis and lateral-torsional coupling in geared systems
has been reported. A number of recent Root Cause Analysis
programs related to turbocompressor string operation problems
(LNG production) have faced barriers due to lack of adequate
torsional vibration monitoring solutions. As the machinery
problems associated with abnormal levels of train torsional
vibration become more frequent, the incentives for the Oil &
Gas industry to address the need for reliable and trouble-free
cyclic torque evaluation gain ground. This constitutes a demand
for a robust, reliable and accurate torsional vibration
monitoring approach acceptable as a practical solution.
Contemporary, industry-wide accepted measurement
technologies (strain gage with telemetry, optical probes, laser)
fit the test needs well but their lack of ruggedness and
durability as well as problematic installation impacting machine
operation do not permit their consideration for long-term
monitoring applications. The authors present a methodology
which allows evaluation of alternating torque amplitudes in
different string sections based on standard instrumentation
installed on the train. The approach adopted in this paper relies
heavily on the modal representation of the dynamic system
being analyzed. The calculation method described utilizes the
results of such analysis along with the angular vibration signal
obtained from standard instrumentation installed on the train
(gas turbine speed pick-up signal spectrum) and typical radial
vibration data from gearbox proximity probes (when available).
This means that no additional probes need to be installed to get
the results.
The robustness and accuracy of the proposed techniques was
validated in the laboratory and benchmarked against test data
from several LNG production train measurement campaigns,
where the alternating torque was measured by means of
standard measurement systems. The authors show the results of
this verification together with prospective system applications.
Description
LectureSubject
TurbomachinesCollections
Citation
Naldi, Lorenzo; Golebiowski, Mateusz; Borown, Adam (2011). NEW APPROACH TO TORSIONAL VIBRATION MONITORING. Turbomachinery Laboratory, Texas A&M Engineering Experiment Station. Available electronically from https : / /hdl .handle .net /1969 .1 /172582.